EPICUTANEOUS APPLICATION OF LEUKOTRIENE B-4 INDUCES PATTERNS OF TENASCIN AND A HEPARAN-SULFATE PROTEOGLYCAN EPITOPE THAT ARE TYPICAL FOR PSORIATIC LESIONS

Application of leukotriene B-4 (LTB4) to normal human skin induces cha nges similar to those found in psoriatic skin, and it has proved to be a useful model for studying the pathogenesis and treatment of psorias is. We studied the expression patterns of molecules that have recently been shown to be altered in lesional psoriatic skin, including the ex tracellular matrix protein tenascin (TN) and the basement membrane and cell surface-associated heparan sulfate proteoglycans (HSPGs), During 72-h the expression of these markers was studied immunohistochemicall y and the expression of TN was correlated with epidermal proliferation and influx of inflammatory cells. Following the peak influx of polymo rphonuclear leukocytes, a marked increase in TN expression was noted i n the papillary dermis 72 h after LTB4 application. The expression pat terns of basal membrane-associated epitopes of HSPG remained unaltered , whereas the expression of cell surface-associated HSPG disappeared 7 2 h after LTB, application, A significant correlation was found betwee n dermal TN expression and epidermal hyperproliferation, and between T N expression and the presence of dermal T cells. These findings indica te that the model of LTB4-induced acute cutaneous inflammation display s many characteristics of early psoriatic: lesions and could serve as a model to study some of the cell biological changes in this disease.